There are numerous methods known in the prior art for providing valve controlled fluid flow in internal combustion engines, and particularly in piston-type engines. Such valves may include pressure-differential responsive poppet-type valves and valves responsive to mechanical actuators such as cams or pushrods. Typical piston-type internal combustion engines are provided with valves disposed in the cylinder head, know as valve-in-head, which permits both relatively simple assembly and operation. A mechanical actuator for operating a valve in such a typical valve-in- head assembly can be located at a fixed position relative to both the valve and the piston crankshaft to ensure proper timing of the valve.
In a dual compression/dual expansion internal combustion engine, such as that disclosed in U.S. Pat. No. 5,456,219, the combustion chamber is disposed within an internal housing or body which oscillates within the external housing of the engine. It is necessary in such an engine to provide one or more intake valves to permit a controlled flow of the initial intake of air into the low pressure compression chamber, and one or more exhaust valves to permit a controlled flow of air and exhaust products from the low pressure expansion chamber. However, in such engines it is also necessary to provide one or more intake transfer valves to permit a controlled flow of air from the low pressure compression chamber to the combustion chamber and one or more exhaust transfer valves to permit a controlled flow of air from the combustion chamber to the low pressure expansion chamber. The intake transfer valves and the exhaust transfer valves must be disposed on and oscillate with the internal body of the engine and are not in a position which is fixed relative to the engine crankshaft. Furthermore, the internal body of such an engine includes two pistons operating in opposition to each other, and there is no cylinder head as such in which a valve assembly and actuators may be conveniently disposed according to the typical valve-in-head configuration. Therefore, an appropriate disposition of the valves and actuating means must be provided.
Furthermore, the typical valve actuating means operates to actuate valves in a fixed position relative to the engine crankshaft, whereas the valve actuating means in a dual compression/dual expansion engine operates on valves which are not fixed relative to the engine crankshaft. The motion of the valves relative to the engine crankshaft, with the resulting changes in distance between the valves and the axis of the engine crankshaft, would require a relatively more complex valve actuating means. Furthermore, even in the event that a mechanical valve train is employed as the valve actuating means, the motion of the internal housing subjects the valve actuating means to substantial forces and accelerations. This increases both the physical size and mass of the components undesirably, in turn increasing the size and weight of the engine. These factors, taken together, essentially prevents the use of the typical valve actuating means.
In addition, the typical valve-in-head assembly can be assembled prior to the installation of the head onto the engine block assembly. Since the internal housing must be assembled prior to installation into the external housing of a dual compression/dual expansion engine, there is no opportunity to assemble conveniently a typical valve actuator means to operate the transfer valves after the basic engine structure of the internal housing and external housing has been assembled.
Therefore, it is an object of the present invention to provide improved valving for a dual compression/dual expansion engine.
It is another object of the present invention to provide such improved valving in the intake transfer valves of the dual compression/dual expansion engine.
It is yet another object of the present invention to provide such improved valving in the exhaust transfer valves of the dual compression/dual expansion engine.
It is a further object of the present invention to provide such improved exhaust transfer valving with an improved valve actuating means.
It is yet a further object of the present invention to provide such an improved exhaust transfer valve actuating means as will substantially reduce the number and size of components required for operating the exhaust transfer valve.
It is yet another object of the present invention to provide such an improved exhaust transfer valve actuating means as will operate reliably.
It is yet another object of the present invention to provide such an improved exhaust transfer valve actuating means as will require relatively low maintenance during its operating lifetime.
It is a further object of the present invention to provide such an improved exhaust transfer valve actuating means as will be relatively inexpensive to manufacture.
It is yet a further object of the present invention to provide a method of assembling such improved valving as will reduce assembly difficulty during assembly.
It is another object of the present invention to provide such a method of assembling such improved valving as will substantially reduce assembly time.
It is yet another object of the present invention to provide such a method of assembling such improved valving as will permit simple assembly of the improved valving with the internal housing prior to assembly thereof with the external housing of the dual compression/dual expansion engine.
These and other objectives of the present invention will become apparent in the specification and claims that follow.